Simulating rainstorm waterlog in piedmont plains in Jinan City

 Urban flooding, due to climate change and rapid urbanization, has become a great challenge for Jinan City. In the present study, Infoworks ICM model was used to simulate rainstorm waterlog in piedmont plains of Jinan. One-dimensional stormwater network model and two-dimensional waterlog model were developed to simulate flood inundation for observed and design rainfalls with different return periods. Distributions of inundation nodes were recorded. Simulation results were compared with actual inundation hydrograph, with the model error further analyzed. Occurrence times of maximum water depth at station mesh for one-and two-dimensional models were found to be 21:50 and 20:05, respectively, consistent with actual records. The two dimensional modeling results showed that maximum water depth was 0.078 which agreed well with observed values. The two-dimensional model performed better in simulations. Rainfall event on 2015-08-03 had a 5 year frequency according to two-dimensional model. One-dimensional model may underestimate inundation. An historical stormwater flood was simulated, design rainfalls with different periods were further simulated, the sources of model error was then analyzed. This work will provide some scientific basis for flood control and disaster reduction, and for the construction of “sponge city” in Jinan.